The present invention is directed to the preparation of a bone plug and tendon graft, in particular, a patella tendon bone autograft.
A common procedure for performing anterior cruciate ligament (ACL) reconstruction involves the use of a central third patella tendon graft. A bone tendon bone graft is harvested. It is then desirable to drill holes in the bone plugs (also called bone blocks) of the graft. The holes are used to thread a suture in one end and a wire in the other end. The suture and wire are for the purpose of locating the graft in the tibial and femoral tunnels. The drilling of these holes has conventionally been accomplished free hand on a platform, which may be PVC coated to have a surface texture of a coarse whetstone. There is a potential in performing such free hand drilling for the surgeon to become injured. The thumb and index finger of the surgeon are holding the bone block during the drilling and are thus in close proximity to the drill. The drill bit could potentially slip off the bone and pierce the gloves of the surgeon. This would transfer patient tissue to the surgeon's finger or thumb via the drill bit wound. A further disadvantage of performing the drilling on the platform is that the drill bit could pierce the PVC, grab some of it and subsequently pass the PVC into the hole in the bone thus contaminating the bone.
Drilling a hole in the block of a graft is difficult to get right when done freehand. If the hole is drilled too far from the end of the bone block, it may disrupt the ACL reconstruction. A suture or wire inserted through the hole is used to pull the bone block through a bone tunnel. If the hole is too far from the end, the bone block may toggle or rotate about the wire in the hole when pulled. This would make it difficult to pull the bone block into the tunnel. Similarly, this difficulty may be encountered if the hole is drilled off-center. Another problem with freehand drilling is that the graft can slip out of the surgeon's fingers and wrap around the drill. This may lead to fracture of the bone block or the graft may slip onto the floor increasing chances of contamination.